Fix issues with Importer's source selector dialog

spine_items/importer/widgets/import_editor_window.py

@@ -14,8 +14,8 @@
 import fnmatch
 import json
 import os
-from PySide6.QtCore import QItemSelectionModel, QModelIndex, Qt, Signal, Slot
-from PySide6.QtWidgets import QDialog, QDialogButtonBox, QFileDialog, QListWidget, QVBoxLayout
+from PySide6.QtCore import QItemSelectionModel, QModelIndex, Qt, QTimer, Signal, Slot
+from PySide6.QtWidgets import QDialog, QDialogButtonBox, QFileDialog, QListWidget, QMessageBox, QVBoxLayout
 from spinedb_api.helpers import remove_credentials_from_url
 from spinedb_api.spine_io.gdx_utils import find_gams_directory
 from spinedb_api.spine_io.importers.csv_reader import CSVConnector
@@ -39,6 +39,18 @@
 from .import_mappings import ImportMappings
 from .import_sources import ImportSources
 
+
+class _ConnectorProblemInMapping(Exception):
+    """Raised when mapping has no connector or the connector looks different to file type."""
+
+    def __init__(self, connector_in_mapping):
+        """
+        Args:
+            connector_in_mapping (type, optional): connector class defined in mapping
+        """
+        self.connector_in_mapping = connector_in_mapping
+
+
 _CONNECTOR_NAME_TO_CLASS = {
     klass.__name__: klass
     for klass in (CSVConnector, ExcelConnector, GdxConnector, JSONConnector, DataPackageConnector, SqlAlchemyConnector)
@@ -106,7 +118,7 @@
         self.connection_failed.connect(self.show_error)
         self._import_sources.preview_data_updated.connect(self._import_mapping_options.set_num_available_columns)
         self._mappings_model.restore(self.specification.mapping if self.specification is not None else {})
-        self.start_ui()
+        QTimer.singleShot(0, self.start_ui)
 
     def is_file_less(self):
         return not self._ui.source_line_edit.text()
@@ -208,26 +220,26 @@
         self.start_ui()
 
     def _get_connector_from_mapping(self, source):
-        """Guesses connector for given source.
+        """Reads connector for given source from mapping.
 
         Args:
             source (str): importee file path or URL
 
         Returns:
-            type: connector class, or None if no suitable connector was found
+            type: connector class
         """
         if not self.specification:
-            return None
+            raise _ConnectorProblemInMapping(None)
         mapping = self.specification.mapping
         source_type = mapping.get("source_type")
         if source_type is None:
-            return None
+            raise _ConnectorProblemInMapping(None)
         connector = _CONNECTOR_NAME_TO_CLASS[source_type]
         file_extensions = connector.FILE_EXTENSIONS.split(";;")
         if source != self._FILE_LESS and not any(fnmatch.fnmatch(source, ext) for ext in file_extensions):
             if connector is SqlAlchemyConnector and self._is_url(source):
                 return connector
-            return None
+            raise _ConnectorProblemInMapping(connector)
         return connector
 
     @Slot()
@@ -263,9 +275,16 @@
 
     def start_ui(self):
         """Connects to source and fills the tables and lists with data."""
-        connector = self._get_connector_from_mapping(self._source)
-        if connector is None:
-            # Ask user
+        try:
+            connector = self._get_connector_from_mapping(self._source)
+        except _ConnectorProblemInMapping as connector_problem:
+            if connector_problem.connector_in_mapping is not None:
+                QMessageBox.warning(
+                    self,
+                    "Verify source type",
+                    f"Source type is set to {connector_problem.connector_in_mapping.DISPLAY_NAME} but the source looks incompatible. "
+                    "You will be prompted to verify the type.",
+                )
             connector = self._get_connector(self._source)
             if not connector:
                 return
@@ -275,6 +294,17 @@
                 self._ui.source_line_edit.clear()
                 self._source = self._FILE_LESS
                 self._source_extras = None
+            if (
+                connector_problem.connector_in_mapping is not None
+                and connector is not connector_problem.connector_in_mapping
+            ):
+                QMessageBox.information(
+                    self,
+                    "Source type changed",
+                    f"Source type changed from {connector_problem.connector_in_mapping.DISPLAY_NAME} to {connector.DISPLAY_NAME}. "
+                    "Don't forget to save the changes.",
+                )
+                self._undo_stack.resetClean()
         connector_name = connector.__name__
         if self._is_database_connector(connector):
             self._ui.source_label.setText("URL:")

tests/data_transformer/test_DataTransformer.py

@@ -24,7 +24,7 @@
 from spine_items.data_transformer.item_info import ItemInfo
 from spine_items.data_transformer.settings import EntityClassRenamingSettings
 from spinedb_api import append_filter_config
-from ..mock_helpers import create_mock_project, create_mock_toolbox, mock_finish_project_item_construction
+from tests.mock_helpers import create_mock_project, create_mock_toolbox, mock_finish_project_item_construction
 
 
 class TestDataTransformer(unittest.TestCase):

tests/exporter/test_Exporter.py

@@ -26,7 +26,7 @@
 from spine_items.utils import database_label
 from spinedb_api import create_new_spine_database
 from spinetoolbox.project_item.logging_connection import LoggingConnection
-from ..mock_helpers import (
+from tests.mock_helpers import (
     clean_up_toolbox,
     create_mock_project,
     create_mock_toolbox,

tests/exporter/widgets/test_specification_editor_window.py

@@ -22,7 +22,7 @@
 from spinedb_api.export_mapping.export_mapping import EntityClassMapping, FixedValueMapping
 from spinedb_api.export_mapping.export_mapping import from_dict as mappings_from_dict
 from spinedb_api.mapping import Position, unflatten
-from ...mock_helpers import clean_up_toolbox, create_toolboxui_with_project
+from tests.mock_helpers import clean_up_toolbox, create_toolboxui_with_project
 
 
 class TestSpecificationEditorWindow(unittest.TestCase):

tests/importer/test_Importer.py

@@ -23,7 +23,7 @@
 from spine_items.importer.importer_factory import ImporterFactory
 from spine_items.importer.importer_specification import ImporterSpecification
 from spine_items.importer.item_info import ItemInfo
-from ..mock_helpers import create_mock_project, create_mock_toolbox, mock_finish_project_item_construction
+from tests.mock_helpers import create_mock_project, create_mock_toolbox, mock_finish_project_item_construction
 
 
 class TestImporter(unittest.TestCase):

tests/importer/widgets/test_ImportPreview_Window.py

@@ -34,6 +34,7 @@ def test_closeEvent(self):
         toolbox.qsettings = mock.MagicMock(return_value=QSettings(toolbox))
         toolbox.restore_and_activate = mock.MagicMock()
         widget = ImportEditorWindow(toolbox, spec)
+        QApplication.processEvents()  # Let QTimer call ImportEditorWindow.start_ui().
         widget._app_settings = mock.NonCallableMagicMock()
         widget.close()
         widget._app_settings.beginGroup.assert_called_once_with("mappingPreviewWindow")

tests/importer/widgets/test_import_editor_window.py

@@ -48,6 +48,7 @@ def test_get_connector_selects_sql_alchemy_connector_when_source_is_url(self):
         with mock.patch("spine_items.importer.widgets.import_editor_window.QDialog.exec") as exec_dialog:
             exec_dialog.return_value = QDialog.DialogCode.Accepted
             editor = ImportEditorWindow(self._toolbox, None)
+            QApplication.processEvents()  # Let QTimer call ImportEditorWindow.start_ui()
             exec_dialog.assert_called_once()
             exec_dialog.reset_mock()
             connector = editor._get_connector("mysql://server.com/db")